import Foundation

enum RedditHomeChromeStyle {
    /// Keeps Reddit header separators flush with the in-app sidebar divider and
    /// fixes Log In / menu hit targets that get covered by borders or feed chrome.
    static let injectionScript = """
    (function() {
      const STYLE_ID = 'reddora-home-chrome-style';
      if (window.__reddoraHomeChromeInstalled) return;
      window.__reddoraHomeChromeInstalled = true;

      const HEADER_ACTION_IDS = ['login-button', 'expand-user-drawer-button'];
      const DECORATIVE_SELECTORS = [
        'faceplate-border',
        'hr',
        '[role="separator"]',
        'shreddit-overlay-display'
      ].join(', ');

      const style = document.createElement('style');
      style.id = STYLE_ID;
      style.textContent = `
        html,
        body,
        shreddit-app {
          margin-top: 0 !important;
          padding-top: 0 !important;
        }

        header,
        header > * {
          margin-left: 0 !important;
        }

        header {
          position: sticky !important;
          top: 0 !important;
          z-index: 300 !important;
          align-items: center !important;
          isolation: isolate !important;
          margin-top: 0 !important;
          padding-top: 0 !important;
          background: var(--shreddit-content-background, #ffffff) !important;
        }

        header faceplate-border,
        header [role="separator"],
        header hr {
          width: 100% !important;
          max-width: none !important;
          margin-left: 0 !important;
          margin-right: 0 !important;
          pointer-events: none !important;
          z-index: 0 !important;
        }

        header faceplate-search-input,
        header #SearchDropdown,
        header [data-testid="search-input-container"] {
          flex: 1 1 auto !important;
          min-width: 0 !important;
          max-width: 100% !important;
          overflow: hidden !important;
          align-self: center !important;
          pointer-events: auto !important;
        }

        /* Wrappers around header actions often extend past the visible button. */
        faceplate-tracker:has(#login-button),
        faceplate-tracker:has(#expand-user-drawer-button),
        rpl-tooltip:has(#login-button),
        rpl-tooltip:has(#expand-user-drawer-button),
        activate-feature:has(#expand-user-drawer-button) {
          display: contents !important;
        }

        #login-button,
        #expand-user-drawer-button {
          position: relative !important;
          z-index: 301 !important;
          pointer-events: auto !important;
          flex-shrink: 0 !important;
          align-self: center !important;
          touch-action: manipulation !important;
        }

        shreddit-overlay-display {
          pointer-events: none !important;
        }

        shreddit-overlay-display:has(
          shreddit-signup-drawer,
          auth-flow-modal,
          input[type="password"]
        ) {
          pointer-events: auto !important;
        }

        /* Feed sort row sits below the header; keep it from overlapping action buttons. */
        shreddit-sort-dropdown,
        [data-testid="sort-dropdown"],
        [data-testid="sort-posts-dropdown"],
        shreddit-feed-sort-dropdown {
          position: relative !important;
          z-index: 1 !important;
        }
      `;

      (document.head || document.documentElement).appendChild(style);

      function isDecorative(node) {
        if (!(node instanceof Element)) return false;
        return node.matches(DECORATIVE_SELECTORS)
          || (node.closest('header') && node.matches('faceplate-border, hr, [role="separator"]'));
      }

      function isInteractive(node) {
        if (!(node instanceof Element)) return false;
        return node.matches(
          'button, a, [role="button"], input, select, textarea, label, faceplate-button'
        );
      }

      function clearBlockersForButton(button) {
        if (!(button instanceof Element)) return;
        const rect = button.getBoundingClientRect();
        if (rect.width < 1 || rect.height < 1) return;

        const sampleYs = [
          rect.top + rect.height * 0.25,
          rect.top + rect.height * 0.5,
          rect.top + rect.height * 0.75,
          rect.bottom - 1
        ];
        const x = rect.left + rect.width * 0.5;

        sampleYs.forEach(function(y) {
          const stack = document.elementsFromPoint(x, y);
          for (let i = 0; i < stack.length; i++) {
            const el = stack[i];
            if (el === button || button.contains(el)) break;
            if (isInteractive(el)) break;
            if (isDecorative(el) || !el.closest('header')) {
              el.style.setProperty('pointer-events', 'none', 'important');
              el.dataset.reddoraPointerFix = '1';
            }
          }
        });
      }

      function pinHeader() {
        document.querySelectorAll('header, reddit-header-large, faceplate-header').forEach(function(node) {
          if (!(node instanceof HTMLElement)) return;
          node.style.setProperty('position', 'sticky', 'important');
          node.style.setProperty('top', '0', 'important');
          node.style.setProperty('z-index', '300', 'important');
          node.style.setProperty(
            'background',
            'var(--shreddit-content-background, #ffffff)',
            'important'
          );
        });
      }

      function patchHeaderHitTargets() {
        pinHeader();

        HEADER_ACTION_IDS.forEach(function(id) {
          const button = document.getElementById(id);
          if (!button) return;
          clearBlockersForButton(button);
          button.style.setProperty('position', 'relative', 'important');
          button.style.setProperty('z-index', '301', 'important');
        });

        document.querySelectorAll('header faceplate-border, header hr, header [role="separator"]').forEach(function(el) {
          el.style.setProperty('pointer-events', 'none', 'important');
        });
      }

      let patchTimer = null;
      function schedulePatch() {
        if (patchTimer) return;
        patchTimer = setTimeout(function() {
          patchTimer = null;
          patchHeaderHitTargets();
        }, 50);
      }

      patchHeaderHitTargets();
      [0, 100, 300, 750, 1500, 3000].forEach(function(delay) {
        setTimeout(patchHeaderHitTargets, delay);
      });

      const observer = new MutationObserver(schedulePatch);
      observer.observe(document.documentElement, { childList: true, subtree: true, attributes: true });

      window.addEventListener('resize', schedulePatch, { passive: true });
      window.addEventListener('scroll', schedulePatch, { passive: true });

      function forwardClicksWithinButtonBounds(event) {
        if (event.type !== 'pointerdown') return;

        const menuButton = document.getElementById('expand-user-drawer-button');
        if (!menuButton || menuButton.contains(event.target)) return;

        const rect = menuButton.getBoundingClientRect();
        const x = event.clientX;
        const y = event.clientY;
        if (x < rect.left || x > rect.right || y < rect.top || y > rect.bottom) return;

        event.preventDefault();
        event.stopImmediatePropagation();
        menuButton.click();
      }

      document.addEventListener('pointerdown', forwardClicksWithinButtonBounds, true);
    })();
    """
}